If you have any doubts about the quality of this database, take comfort in the fact that its creators are from the Best Institute for Medical Research (no joke) at the University of Toronto. This database presents the protein content of six organs (liver, lung, placenta, brain, heart, and kidney) in the mouse, which is further characterized by cellular compartment (cytosol, membranes, mitochondrion, nucleus). How did the researchers do this, you ask? Through a lot of work. Just reading about their “exhaustive mass spectrometry-based shotgun sequencing” made my head hurt. The result is comprehensive and nicely organized, with numerous ways to search and sort the information. There is also a BLAST feature whereby one can input an amino acid sequence and search the database. All in all, it’s a useful tool for researchers.